No. II.] THE BRYOPHYTES OF CONNECTICUT. 23 



three longitudinal rows. The leaves vary in form from linear 

 to orbicular, and, although they are sometimes toothed or 

 even ciliate on the margins, they are never deeply lobed or 

 divided as in some of the Jungermanniaceae. Except for the 

 midrib, which may or may not be present, the leaves very 

 rarely . show any differentiation in their cells. In prostrate 

 species the plants sometimes acquire a dorsi-ventral appearance, 

 and a slight differentiation in the leaves is occasionally to be 

 observed. These peculiarities, however, are never so clearly 

 marked as in the Jungermanniaceae, and there is little danger 

 of confusing the True Mosses with the Scale Mosses. The 

 branching in the Bryales is always of the monopodial type, and 

 is often distinctly pinnate. In the lower forms the stem 

 presents a simple and uniform structure, but in some of the 

 higher genera it shows a distinct cell differentiation into 

 storage, strengthening, and conducting tissues, and the same 

 is sometimes true of the midribs of the leaves. 



In the majority of cases the sporophyte shows a distinct 

 foot, a firm stalk, which early becomes elongated, and a highly 

 complex capsule. The calyptra at first keeps pace with the 

 lengthening sporophyte but soon stops growing and becomes 

 ruptured. In nearly every case the line of rupture is near the 

 base, and the calyptra is carried up on the tip of the sporophyte. 

 As the capsule gradually enlarges, the calyptra, which is now 

 cut off from its source of food-supply, dries up and splits in 

 one or more places, so that it frequently falls away long before 

 the spores are mature. The spore cavity occupies a relatively 

 small space in an immature capsule, and is in the form of a 

 hollow cylinder open at both ends, differing in this respect 

 from all the preceding Bryophytes. It encloses a massive 

 columella, and is bounded by a thick wall, which, in most 

 species, represents an efficient photosynthetic tissue. The 

 outer cell layer of the wall forms an epidermis with stomata, 

 the latter being usually restricted to the base of the capsule. 

 The green cells are usually arranged in two more or less 

 definite layers, one surrounding the spore cavity and the other 

 lining the epidermis. These two layers are separated by a 

 large air space in the form of a hollow cylinder. Stretching 

 across the air space from one green layer to the other are 



